The invention herein resides in the art of power transmission devices and, more particularly, to couplers between a power source and a power driven implement. More particularly, the invention relates to power takeoff units. Specifically, the invention relates to a power takeoff clutch assembly adapted for controlled engagement and having a diagnostic system for monitoring and assessing its use and operation.
The use of clutches of various types to couple power from a power source such as an engine to auxiliary pieces of equipment is commonly known. Presently, over center mechanical engine clutches are often used to couple the flywheel of an engine to an auxiliary piece of equipment. Such clutches suffer from a number of problems, including pilot bearing failures, excessive wear, frequent adjustment and maintenance and operator abuse while attempting to achieve engagement when the clutch is coupling the engine with a high inertia load such as crushers and hammer mills. Indeed, in view of the state of the prior art, there is a need for a hydraulically actuated, wet multiple disk clutch to serve as a power takeoff unit between an engine and a high inertia load. Moreover, there is a need in the art for such a power takeoff unit which can serve as a torque limiter, while also providing a means for driving auxiliary hydraulic pumps. Further, there remains a need in the art for such a power takeoff unit which may easily and effectively be engaged to connect a high inertia load.
There is further a need in the art for a technique and apparatus for engaging power sources with high inertia loads in a prompt and efficient manner, without stalling or otherwise overloading the power source.
Moreover, it is presently known in the power transmission industry that industrial diesel engines can be used to power rotary cutter heads on equipment such as grinders, shredders, and chippers for the waste recycling market. It is also well known in the industry, that some form of power transmission device is required to interface between the engine and the driven equipment. It is customary to classify such a power transmission device as a clutching device; such as a hydraulic, pneumatic, or electrically actuated engagement device. That is to say a xe2x80x9cclutchxe2x80x9d is classified as a device for engaging and disengaging an engine to a driven load. These clutches typically suffer damage and abuse caused by harsh duty cycles and operator actions and/or lack of response. With no means for monitoring such duty cycles and operator actions, manufacturers are left without knowledge of the cause of many failures and are thus unable to remedy recurring problems. Additionally, such manufacturers are often unable to distinguish between failures resulting from design or manufacturing shortcomings and those resulting from operator abuse.
Accordingly, there is a need in the art for a diagnostic system implemented with a power source and power takeoff unit that can monitor the operational activities of both, and which can record and assess associated operator actions.
In light of the foregoing, it is a first aspect of the invention to provide a hydraulically actuated power takeoff clutch unit in which the input end of the clutch thereof is rigidly and directly coupled to the engine flywheel, without the need for bearing support of the clutch input.
Still a further aspect of the invention is the provision of a hydraulically actuated power takeoff clutch unit which includes a gear on the input of the clutch assembly which may be employed to drive hydraulic pumps for powering auxiliary equipment, or for actuating the hydraulically actuated power takeoff clutch unit itself.
Yet another aspect of the invention is the provision of a hydraulically actuated power takeoff clutch unit which provides for ease of removal of a clutch module while allowing the remainder of the unit to stay secured to the engine itself, thus allowing for servicing of the clutch assembly without removal of the entirety of the power takeoff clutch unit and pump drives from the engine.
Yet a further aspect of the invention is the provision of a hydraulically actuated power takeoff clutch unit which employs an automatic brake structure which retards rotation of the output shaft except when the clutch is engaged.
Still another aspect of the invention is the provision of a hydraulically actuated power takeoff clutch unit which employs a rotary union for coupling hydraulic, cooling and lubricating fluids to the clutch assembly.
Still a further aspect of the invention is to provide a hydraulically actuated power takeoff clutch unit which is electronically controlled so as to achieve effective start-up and controlled operation.
Yet a further aspect of the invention is to provide a hydraulically actuated power takeoff clutch unit which is reliable and durable in operation, readily constructed from state of the art components, and readily adapted to implementation with existing equipment.
Another aspect of the invention is the provision of a power takeoff clutch assembly and diagnostic system in which engagement of the clutch, whether hydraulic, pneumatic, mechanical or electrical, is attained through sequential steps, providing increased opportunity for engagement to occur without stalling the power source.
A further aspect of the invention is the provision of a power takeoff clutch assembly and diagnostic system in which various operational parameters involving the clutch and associated power source are continually monitored and assessed to detect operational failures and their causes and prevent the same.
The foregoing and other aspects of the invention which will become apparent as the detailed description proceeds are achieved by a method for operationally interconnecting a power source and a load through a clutch, comprising: engaging the clutch; monitoring the speed of the power source; and sequentially disengaging the clutch if the speed of the power source drops below a first threshold and re-engaging the clutch if the speed of the power source exceeds a second threshold.
Other aspects of the invention are attained by a method for controlling and monitoring the operative interengagement of a power source and load through a clutch, comprising: sensing the speed of the power source; sensing the oil pressure and temperature of the clutch; and controlling the engagement and disengagement of the clutch as a function of said speed, oil pressure and temperature.